Convertible sofa

ABSTRACT

The present invention is for a method of converting a standard jack knife hinge into a new hinge, which allows access to a storage area underneath the seat bottom while retaining the ability to be used as a sofa and a bed. The new hinge is created by removing the seat bottom frame from the seat bottom bracket, fixably attaching a first attachment bracket to the seat bottom frame, pivotally attaching the first attachment bracket to a second attachment bracket, and fixably attaching the seat bottom bracket and the second attachment bracket to the seat base frame. The present invention also claims the finished combined hinge as well as a convertible sofa utilizing the new hinge.

FIELD OF THE INVENTION

[0001] This invention relates to a convertible sofa and, moreparticularly, to a convertible sofa or seat for use on recreationalvehicles which can be converted from a seat to a bed.

BACKGROUND OF THE INVENTION

[0002] In many recreational vehicles today, it is common to have aconvertible sofa or seat bed, which can function as a seat, a sofa, or abed. Such seats are typically employed on recreational vehicles, but canalso be used in extended cab pickups, vans, and minivans. The seat isoften configured to fold into a flat, planar configuration for use as abed, and then fold at a juncture between the seat bottom and the seatback so as to form a seat or sofa. The prior art seats have accomplishedthis versatility by the use of a standard jack knife hinge, which isshown in FIGS. 1 and 2 and will be discussed in detail below.

[0003] It is also common in recreational vehicles today to optimize theavailable space therein for maximum possible usage. Given the economicand fuel efficiency drawbacks of increasing the size of the vehicle,manufacturers are continually redesigning vehicle ergonomics to takemaximum advantage of available interior space. One prior art devicecomprises a seat wherein the seat bottom can be folded parallel to theseat back to increase the storage space of the vehicle and to access aspace provided below the seat. However, this prior art design hasseveral limitations. It does not allow the seat back to fold over theseat bottom to allow greater access behind the seat back or to allowmore room for storage. This prior art design also requires the use of ahinge plate between the seat and the seat back making the constructionrelatively complex and, possibly, allowing accidental insertion offingers, which can cause serious injury. This prior art design alsocannot be easily retrofitted, as it requires replacement of the standardjack knife design.

SUMMARY OF THE INVENTION

[0004] The convertible sofa of this invention provides a simple seatbottom hinge and seat back hinge, which are designed to be used incombination with a standard jack knife hinge. The new invention willallow the seat bottom to be rotated upwards and generally parallel tothe seat back in order to increase the storage space of the vehicle andto provide access to a space provided below the seat. The new inventionwill also allow normal operation of the standard jack knife hinge, whichallows the sofa to be converted into a bed when the seat bottom is down.

[0005] These and other advantages are provided by a method of making animproved convertible sofa hinge from a standard convertible sofa jackknife hinge. The jack knife hinge connects a seat back frame and a seatbottom frame to a seat base frame including a side rail. The jack knifehinge has a seat back bracket fixably connected to the seat back frame,a seat bottom bracket fixably connected to the seat bottom frame, theseat back bracket pivotally connected to the seat bottom bracket, afirst pivot arm pivotally connected to the side rail and the seat backbracket, a second pivot arm pivotally connected to the side rail and theseat bottom bracket, and the cross bar arm pivotally attached to thefirst pivot arm and the second pivot arm. The method of making the animproved convertible sofa hinge comprises the steps of: a) removing theseat bottom frame from the seat bottom bracket; b) fixably attaching afirst attachment bracket to the seat bottom frame; c) pivotallyattaching the first attachment bracket to a second attachment bracket;and d) fixably attaching the seat bottom bracket and the secondattachment bracket to the seat base frame.

[0006] These and other advantages are also provided by a hinge assemblyfor a convertible sofa, wherein the hinge connects a seat back frame anda seat bottom frame to a seat base frame including a side rail. Thehinge for a convertible sofa comprises a seat back bracket fixablyconnected to the seat back frame, a seat bottom bracket pivotallyconnected to the seat back bracket, a first pivot arm pivotallyconnected to the side rail and the seat back bracket, a second pivot armpivotally connected to the side rail and the seat bottom bracket, across bar arm pivotally attached to the first pivot arm and the secondpivot arm, a first attachment bracket fixably attached to the seatbottom frame, and a second attachment bracket pivotally attached thefirst attachment bracket. The seat bottom bracket and the secondattachment bracket are fixably attached to the seat base frame.

[0007] These and other advantages are also provided by a convertiblesofa comprising a seat back frame, a seat bottom frame, and a seat baseframe including a side rail on opposite sides of the seat base framewherein the seat base frame encloses a storage area. The sofa furthercomprises a pair of hinges connecting the seat back frame and the seatbottom frame to the seat base frame. Each hinge comprises a seat backbracket fixably connected to the seat back frame, a seat bottom bracketpivotally connected to the seat back bracket, a first pivot armpivotally connected to the side rail and the seat back bracket, a secondpivot arm pivotally connected to the side rail and the seat bottombracket, a cross bar arm pivotally attached to the first pivot arm andthe second pivot arm, a first attachment bracket fixably attached to theseat bottom frame, and a second attachment bracket pivotally attachedthe first attachment bracket. The seat bottom bracket and the secondattachment bracket are fixably attached to the seat base.

[0008] These and other advantages of this invention will become apparentupon a reading of the following description.

BRIEF DESCRIPTION OF THE DRAWING

[0009] A preferred embodiment of the invention has been depicted forillustrative purposes wherein:

[0010]FIG. 1 is a side elevational view of a prior art convertible sofautilizing a standard jack knife hinge assembly shown in the seatposition with portions shown in section and the cushions shown in brokenlines for purposes of illustration.

[0011]FIG. 2 is a perspective view of the prior art convertible sofa ofFIG. 1 shown in the bed position;

[0012]FIG. 3 is an exploded perspective view of a seat bottom hingeassembly of the present invention;

[0013]FIG. 4 is an assembled perspective view of the seat bottom hingeassembly shown in FIG. 3;

[0014]FIG. 5 is a partially exploded perspective view of the seat bottomhinge assembly attached to the seat bottom frame assembly over top of aseat frame assembly including a jack knife hinge assembly;

[0015]FIG. 6 is a perspective view of the seat bottom hinge assemblyattached to the seat bottom frame assembly;

[0016]FIG. 7 is a perspective view of an embodiment of the convertiblesofa utilizing the seat bottom hinge assembly of the present inventionshown in a sofa or seat configuration;

[0017]FIG. 8 is a perspective view of an embodiment of the convertiblesofa utilizing the seat bottom hinge assembly of the present inventionshown in a lifted seat bottom configuration;

[0018]FIG. 9 is an exploded perspective view of a seat back hingeassembly of an embodiment of the present invention;

[0019]FIG. 10 is an assembled perspective view of the seat back hingeassembly shown in FIG. 9;

[0020]FIG. 11 is a perspective view of the seat back hinge assembly asshown in FIG. 9 attached to a seat back frame assembly;

[0021]FIG. 12 is a partially exploded perspective view of the seat backhinge assembly attached to the seat bottom frame assembly displaced overa seat frame assembly including a jack knife hinge assembly;

[0022]FIG. 13 is a perspective view of an embodiment of the convertiblesofa utilizing the seat bottom hinge assembly and utilizing the seatback hinge assembly of the present invention in a sofa or seatconfiguration;

[0023]FIG. 14 is a perspective view of an embodiment of the convertiblesofa utilizing the seat bottom hinge assembly and the seat back hingeassembly of the present invention shown in a lowered seat backconfiguration;

[0024]FIG. 15 is an exploded perspective view of an alternate embodimentof a seat bottom hinge assembly of the present invention;

[0025]FIG. 16 is a perspective view of the seat bottom hinge assembly ofFIG. 15 attached to the seat bottom frame assembly;

[0026]FIG. 17 is a partially exploded perspective view of the seatbottom hinge assembly of FIG. 15 attached to the seat bottom frameassembly over top of a seat frame assembly including a jack knife hingeassembly;

[0027]FIG. 18 is an exploded perspective view of another alternateembodiment of a seat bottom hinge assembly of the present invention;

[0028]FIG. 19 is a perspective view of the seat bottom hinge assembly ofFIG. 18 attached to the seat bottom frame assembly;

[0029]FIG. 20 is a partially exploded perspective view of the seatbottom hinge assembly of FIG. 18 attached to the seat bottom frameassembly over top of a seat frame assembly including a jack knife hingeassembly;

[0030]FIG. 21 is a perspective view of an embodiment of the convertiblesofa utilizing the seat bottom hinge assembly shown in FIG. 18 of thepresent invention shown in a sofa or seat configuration;

[0031]FIG. 22 is a perspective view of an embodiment of the convertiblesofa utilizing the seat bottom hinge assembly shown in FIG. 18 of thepresent invention shown in a lifted seat bottom configuration;

[0032]FIG. 23 is a perspective view of an unlocking strap assembly ofthe present invention used with a convertible sofa utilizing the seatbottom hinge assembly shown in FIG. 18 of the present invention shown ina lifted seat bottom configuration;

[0033]FIG. 24 is a perspective view of the actuator strap loop of theunlocking strap assembly of FIG. 23 extending from a convertible sofautilizing the seat bottom hinge assembly shown in FIG. 18 of the presentinvention shown in a lifted seat bottom configuration;

[0034]FIG. 25 is an exploded perspective view of another alternateembodiment of a seat bottom hinge assembly of the present invention;

[0035]FIG. 26 is a perspective view of the seat bottom hinge assembly ofFIG. 25 attached to the seat bottom frame assembly; and

[0036]FIG. 27 is a perspective view of an embodiment of the convertiblesofa utilizing the seat bottom hinge assembly shown in FIG. 25 of thepresent invention shown in a lifted seat bottom configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0037] Referring to FIGS. 1 and 2 of the drawings, a prior artconvertible sofa bed 10 utilizing a standard jack knife hinge 25 isshown. The convertible sofa bed 10 comprises generally a seat backcushion 24 attached to a seat back frame 22 and a seat bottom cushion 20attached to a seat bottom frame 18, both supported by seat frame 12through a jack knife hinge 25. The prior art jack knife hinge 25comprises a seat bottom mounting bracket 26 secured to the rear of seatbottom frame 18 by bolts 29 and a seat back mounting bracket 28 securedto the lower end of seat back frame 22 by bolts 31. Mounting brackets26, 28 are secured to one another by a pivot bolt 27. A first pivot arm30 is connected at one end to seat bottom mounting bracket 26 by afastener 16 and, at its other end, to frame 21 by a pivot pin 34. Asecond pivot arm 36 is connected at one end to seat back mountingbracket 28 by fastener 38 and, at its other end, to frame 21 by pivotpin 40. A cross pivot arm 42 is connected to first pivot arm 30 betweenits ends by fastener 44 and to second pivot arm 36 between its ends byfastener 46. The jack knife hinge 25 allows the convertible sofa bed 10to be configured in a sofa or seat configuration as shown in FIG. 1 orin a bed configuration as shown in FIG. 2.

[0038] A first embodiment of the present invention utilizes a seatbottom hinge assembly 41 shown in an exploded and assembled view inFIGS. 3 and 4, respectively. Seat bottom hinge assembly 41 comprisesfirst attachment bracket 43 and a rotatable second inner attachmentbracket 45. First attachment bracket 43 comprises a generally verticalportion 47 having a first and a second generally horizontally projectingfastener 48 and 50, respectively. First attachment bracket 43 alsocomprises a generally horizontal portion 52 having a first and secondgenerally vertically projecting fastener 54 and 56, respectively. Secondinner attachment bracket 45 comprises a generally horizontal portion 59adapted for securing second inner attachment bracket 45 to a bottom seatframe assembly 80. Second inner attachment bracket 45 also comprises agenerally vertical portion 57 having a first slot 58 and second slot 60through which first and second fasteners 48 and 50 extend through whensecond inner attachment bracket 45 is assembled onto first attachmentbracket 43 and secured thereto by nuts 62. First slot 58 is generallyhorizontal and provides a pivot point about which second innerattachment bracket 45 rotates with respect to first attachment bracket43. Rotation is controlled by second slot 60, which generally comprisesan arcuate portion 64 terminating into a horizontal portion 66. Secondinner attachment bracket 45 may also include a spring-loaded lock pinassembly 68, which will prevent second inner attachment bracket 45 fromrotating with respect to first attachment bracket 43, as will bediscussed in greater detail below.

[0039] Referring now to FIG. 6, seat bottom hinge assembly 41 is shownattached to seat bottom frame assembly 80. This attachment may beaccomplished by utilizing fasteners, welding, or any other appropriatefastening means. In FIG. 5, seat bottom frame assembly 80 with attachedseat bottom hinge assembly 41 is shown in a partially exploded view overtop a seat frame assembly 90 including a jack knife hinge 100. First andsecond vertically projecting fasteners 54 and 56 extend throughapertures 102 in a seat bottom mounting bracket 104 of jack knife hinge100 and attached thereto by nuts 62. This attachment may be also beaccomplished by welding, or any other appropriate fastening means.

[0040] In FIG. 7, a convertible sofa bed 110 is shown including seatbottom hinge assembly 41 of the present invention attached to seatbottom frame assembly 80, including a jack knife hinge 100 configured ina seat configuration. In FIG. 8, the convertible sofa bed 110 is shownwith seat bottom frame assembly 80 in a raised configuration providingaccess to the area below seat frame assembly 90. In order to move seatbottom frame assembly 80 into a raised position, seat bottom frameassembly 80 must be pulled generally horizontally in a direction awayfrom seat back frame assembly 180 such that second fastener 50 of firstattachment bracket 43 slides from the horizontal portion 66 of secondslot 60 and into the arcuate portion 64 of second slot 60 as best shownin FIG. 6. This enables seat bottom frame assembly 80 to be liftedupwards about the pivot point 57 formed by first fastener 48 of thefirst attachment bracket 43 and the end of the generally horizontalfirst slot 58. Attempting to lift seat bottom frame assembly 80 withoutfirst pulling outward horizontally away from seat back frame assembly180 will not result in the seat bottom frame assembly 80 moving upwardas the horizontal portion 66 of second slot 60 will prevent thismovement. Once the seat bottom frame assembly 80 has been completelyrotated upward, spring-loaded lock pin assembly 68 will engage anaperture 88 on first attachment bracket 43, thereby locking seat bottomframe assembly 80 in an upright position. In order to return theconvertible sofa bed 110 to the seat position configuration, thespring-loaded lock pin assembly 68 is disengaged, allowing seat bottomframe assembly 80 to rotate downward to its initial generally horizontalposition. Returning seat bottom frame assembly 80 to the seatconfiguration will allow the convertible sofa bed 110 to work as astandard jack knife hinged sofa bed.

[0041] A second embodiment of the present invention utilizes a seat backhinge assembly 141 shown in an exploded and assembled view in FIGS. 9and 10, respectively. Seat back hinge assembly 141 comprises firstattachment bracket 143 and a rotatable second attachment bracket 145.First attachment bracket 143 comprises a first generally planar portion146 having a first and a second generally perpendicularly projectingfastener 148 and 150, respectively, and an aperture 188. Firstattachment bracket 143 also comprises a second generally planar portion152, generally perpendicular to first planar portion 146, including afirst and a second projecting fastener 154 and 156, respectively. Secondattachment bracket 145 comprises a first planar portion 159 adapted forsecuring second attachment bracket 145 to a bottom seat frame assembly180. Second attachment bracket 145 also comprises a second generallyplanar portion 157 having a slot 158 and an aperture 160 through whichfirst and second fasteners 148 and 150 extend through when secondattachment bracket 145 is assembled onto first attachment bracket 143and secured thereto by nuts 62. Aperture 160 provides a pivot pointabout which second attachment bracket 145 rotates with respect to firstattachment bracket 143. Rotation is controlled by slot 158, which isgenerally arcuate. Second attachment bracket 145 may also include aspring-loaded lock pin assembly 168, which mates with aperture 188 inthe first attachment bracket 143, as best shown in FIG. 9. Spring-loadedlock pin assembly 168 engages aperture 188 to prevent second attachmentbracket 145 from rotating with respect to first attachment bracket 143when the seat back frame assembly 180 is in an upright position in aseat configuration. When the spring-loaded lock pin assembly 168 isdisengaged, the seat back frame assembly 180 is free to rotate downwardtoward the seat bottom frame assembly 80.

[0042] Referring now to FIG. 11, seat back hinge assembly 141 is shownattached to seat back frame assembly 180. This attachment may beaccomplished by utilizing fasteners, welding, or any other appropriatefastening means. In FIG. 12, seat back frame assembly 180, with attachedseat back hinge assembly 141, is shown in a partially exploded viewdisplaced over a seat frame assembly 190, including a jack knife hinge100. First and second perpendicularly projecting fasteners 154 and 156extend through apertures 106 in a seat back mounting bracket 108 of jackknife hinge 100 and attached thereto by nuts 62. This attachment may bealso be accomplished by welding, or any other appropriate fasteningmeans.

[0043] In FIG. 13, a convertible sofa bed 210 is shown, including seatback hinge assembly 141 of the present invention, attached to seat backframe assembly 180 including a jack knife hinge 100, configured in aseat configuration. In FIG. 14, the convertible sofa bed 210 is shownwith seat back frame assembly 180 in a lowered configuration, providingaccess to the area behind seat frame assembly 90. In order to move seatback frame assembly 180 into a lowered position, spring-loaded lock pinassembly 168 must be disengaged from aperture 188 such that the seatback frame assembly 180 is free to rotate downward toward the seatbottom frame assembly 80. In order to return the convertible sofa bed210 to the seat position configuration, seat back frame assembly 180 isrotated upward until the spring-loaded lock pin assembly 168 engagesaperture 188, locking the seat back frame assembly 180 into position.

[0044] A third embodiment of the present invention utilizes a seatbottom hinge assembly 241 shown in an exploded view in FIG. 15, shownattached to a seat bottom frame assembly 280 in FIG. 16, and shownattached to a seat assembly 290 in FIG. 17. This embodiment is similarto the first embodiment except that the bottom seat frame assembly 280is pushed inwards, then lifted, instead of pulled outward, then lifted.

[0045] Seat bottom hinge assembly 241 comprises a first or lowerattachment bracket 243 and a rotatable second or upper attachmentbracket 245. Lower attachment bracket 243 comprises a first planarportion 247 having a perpendicularly projecting front travel pin 248, amain pivot pin 250, a rear travel slot 270 and a locking aperture 272.Lower attachment bracket 243 also comprises a second planar portion 252generally perpendicular to first planar portion 247 having a first andsecond generally vertically projecting fastener 254 and 256,respectively. Upper attachment bracket 245 comprises a first planarportion 259 adapted for securing upper attachment bracket 245 to abottom seat frame assembly 280. Upper attachment bracket 245 alsocomprises a second portion 257 generally perpendicular to first planarportion 259 having a first slot 258 and second slot 260 through whichfront travel pin 248 and main pivot pin 250 extend through when upperattachment bracket 245 is assembled onto lower attachment bracket 243and secured thereto by nuts 62 (not shown). Second portion 257 of upperattachment bracket 245 also comprises a rear travel pin 274 which mateswith rear travel slot 270, and an aperture 260 (not shown) for mountingspring-loaded lock pin assembly 168.

[0046] First slot 258 is generally horizontal and provides a pivot pointabout which upper attachment bracket 245 rotates with respect to lowerattachment bracket 243. Rotation is controlled by front travel slot 260,which generally comprises an arcuate portion 264 terminating into ahorizontal portion 266 and rear travel slot 261, which generallycomprises an arcuate portion 263 terminating into a horizontal portion265. Upper attachment bracket 245 may also include a spring-loaded lockpin assembly 168, which will prevent upper attachment bracket 245 fromrotating with respect to lower attachment bracket 243, similar to thatdiscussed in relation to the first embodiment.

[0047] Referring now to FIG. 16, seat bottom hinge assembly 241 is shownattached to seat bottom frame assembly 280. This attachment may beaccomplished by utilizing fasteners, welding, or any other appropriatefastening means. In FIG. 17, seat bottom frame assembly 280 withattached seat bottom hinge assembly 241 is shown in a partially explodedview over top a seat frame assembly 290 including a jack knife hinge100. First and second vertically projecting fasteners 254 and 256 extendthrough apertures 102 in a seat bottom mounting bracket 104 of jackknife hinge 100 and attached thereto by nuts 62. This attachment may bealso be accomplished by welding, or any other appropriate fasteningmeans.

[0048] In order to move seat bottom frame assembly 280 into a raisedposition, seat bottom frame assembly 280 must be pushed generallyhorizontally in a direction toward seat back frame assembly 180 suchthat front travel pin 250 of lower attachment bracket 243 slides fromthe horizontal portion 266 of front travel slot 260 and into the arcuateportion 264. Similarly, rear travel pin 274 of upper attachment bracket245 slides from the horizontal portion 265 of rear travel slot 270 andinto the arcuate portion 264. This enables seat bottom frame assembly280 to be lifted upwards about the pivot point formed by main pivot pin248 of the lower attachment bracket 243 and the end of the generallyhorizontal first slot 258. Attempting to lift seat bottom frame assembly280 without first pushing inward horizontally toward seat back frameassembly 180 will not result in the seat bottom frame assembly 280moving upward as the horizontal portion 266 of front travel slot 260 andthe horizontal portion 265 of rear travel slot 270 will prevent thismovement. Once the seat bottom frame assembly 280 has been completelyrotated upward, spring-loaded lock pin assembly 168 will engage aperture272 on lower attachment bracket 243, thereby locking seat bottom frameassembly 280 in an upright position. In order to return to the seatposition configuration, the spring-loaded lock pin assembly 168 isdisengaged, allowing seat bottom frame assembly 280 to rotate downwardto its initial generally horizontal position.

[0049] A fourth embodiment of the present invention utilizes a seatbottom hinge assembly 341 shown in a disassembled view in FIG. 18. Thisembodiment is different from the first and third embodiments in that theseat bottom hinge assembly 341 is locked in both the upright andlowered, or seat configurations such that the seat bottom frame assembly380 does not need to be either pulled or pushed to allow movement, butrather must be unlocked. Seat bottom hinge assembly 341 comprises firstattachment bracket 343 and a rotatable second attachment bracket 345.First attachment bracket 343 comprises a first generally planar portion347 having a pivot point aperture 388 and a seated locking positionaperture 348 and an open locked position aperture 350. First attachmentbracket 343 also comprises a second generally planar portion 352,generally perpendicular to first planar portion 346, including a firstand a second projecting fastener 354 and 356, respectively. Secondattachment bracket 345 comprises a first planar portion 359 adapted forsecuring second attachment bracket 345 to a bottom seat frame assembly380. Second attachment bracket 345 also comprises a second generallyplanar portion 357 having a pivot point aperture 358 and a secondaperture 360 for mounting spring-loaded lock pin assembly 168 (notshown). First attachment bracket 343 is attached to second attachmentbracket 345 by a bolt 375 extending through pivot point apertures 388and 358, respectively, and secured thereto by nut 62. Apertures 388 and358 provide a pivot point about which second attachment bracket 345rotates with respect to first attachment bracket 343. Second attachmentbracket 345 includes a spring-loaded lock pin assembly 168, which mateswith seated locking position aperture 348 when seat bottom frameassembly 380 is in a lowered, or seat position. Spring-loaded lock pinassembly 168, also mates with open locked position aperture 350 whenseat bottom frame assembly 380 is in a raised or open position.Spring-loaded lock pin assembly 168 engages apertures 350, 388 toprevent second attachment bracket 345 from rotating with respect tofirst attachment bracket 343 when the seat bottom frame assembly 380 isin an upright position or in a seat configuration. When thespring-loaded lock pin assembly 168 is disengaged, the seat bottom frameassembly 380 is free to rotate downward toward the seat frame assembly390, or upward to a raised position.

[0050] Referring now to FIG. 19, seat bottom hinge assembly 341 is shownattached to seat bottom frame assembly 380. This attachment may beaccomplished by utilizing fasteners, welding, or any other appropriatefastening means. In FIG. 20, seat bottom frame assembly 380, withattached seat bottom hinge assembly 341, is shown in a partiallyexploded view displaced over a seat frame assembly 390, including a jackknife hinge 100. First and second perpendicularly projecting fasteners354 and 356 extend through apertures 102 in a seat bottom mountingbracket 104 of jack knife hinge 100 and attached thereto by nuts 62.This attachment may be also be accomplished by welding, or any otherappropriate fastening means.

[0051] In FIG. 21, a convertible sofa bed 310 is shown, including seatbottom hinge assembly 341 of the present invention, attached to seatbottom frame assembly 380 including a jack knife hinge 100, configuredin a seat configuration. In FIG. 22, the convertible sofa bed 310 isshown with seat bottom frame assembly 380 in a raised configuration,providing access to the area below seat frame assembly 390. In order tomove seat bottom frame assembly 380 into a raised or lowered position,spring-loaded lock pin assembly 168 must be disengaged from aperture350, 348 respectively, such that the seat bottom frame assembly 180 isfree to rotate downward toward the seat frame assembly 390. Once seatbottom frame assembly 380 is rotated to the selected position,spring-loaded lock pin assembly 168 automatically engages thecorresponding aperture 350, 348 of the new position.

[0052] In another embodiment of the present invention, the spring-loadedlock pin assemblies 168 on either side of convertible sofa bed 310 canbe disengaged using an unlocking strap assembly 400 as best shown inFIG. 23. Strap assembly 400 comprises a first strap 402 extendingbetween the spring-loaded lock pin assemblies 168 on either side ofconvertible sofa bed 310. An actuator strap 404 is attached to amidportion of the first strap and extends from the rear to the front ofseat bottom frame 380. A loop 406, or tab portion, extends fromunderneath seat bottom frame 380 as best shown in FIG. 24. Pulling onloop 406 causes tension on first strap 402 and disengages spring-loadedlock pin assemblies 168. This allows the seat bottom frame 380 to rotateeither to a raised position or a lowered seat configuration.

[0053] In another embodiment of the present invention, a seat bottomhinge assembly 441 is shown in FIGS. 25-27. Seat bottom hinge assembly441 is similar to the first embodiment in that the actuation isidentical; pull the seat bottom assembly 480 outward and rotate up untilit locks. The difference between these embodiments is that the firstattachment bracket 443 and second attachment bracket 445 extend downwardinstead of upward. FIG. 25 shows first attachment bracket 443 attachedto seat bottom assembly 480. FIG. 26 shows second attachment bracket 445being attached to the first attachment bracket 443 on seat bottomassembly 480. FIG. 27 shows the operation of seat bottom hinge assembly441 in a raised configuration on a convertible sofa bed 410.

[0054] It is contemplated that any of the seat bottom hinge embodimentscan be used with the seat top embodiment, or if appropriate, used inplace of a seat top embodiment as well.

[0055] Although the present invention has been described above indetail, the same is by way of illustration and example only and is notto be taken as a limitation on the present invention. Accordingly, thescope and content of the present invention are to be defined only by theterms of the appended claims.

What is claimed is:
 1. A method of making an improved convertible sofahinge from a standard convertible sofa jack knife hinge, the jack knifehinge connecting a seat back frame and a seat bottom frame to a seatbase frame including a side rail, the jack knife hinge having a seatback bracket fixably connected to the seat back frame, a seat bottombracket fixably connected to the seat bottom frame, the seat backbracket pivotally connected to the seat bottom bracket, a first pivotarm pivotally connected to the side rail and the seat back bracket, asecond pivot arm pivotally connected to the side rail and the seatbottom bracket, the cross bar arm pivotally attached to the first pivotarm and the second pivot arm, the method comprising the following steps:a) removing the seat bottom frame from the seat bottom bracket; b)fixably attaching a first attachment bracket to the seat bottom frame;c) pivotally attaching the first attachment bracket to a secondattachment bracket; and d) fixably attaching the seat bottom bracket andthe second attachment bracket to the seat base frame.
 2. The method ofclaim 1 further comprising the following steps: e) removing the seatback frame from the seat back bracket; f) fixably attaching a thirdattachment bracket to the seat back frame; g) pivotally attaching thethird attachment bracket to a fourth attachment bracket; and h) fixablyattaching the fourth attachment bracket to the seat back bracket.
 3. Themethod of claim 1 further comprising the following steps: e) attaching alocking pin to the first attachment bracket; f) providing an aperture inthe second attachment bracket such that the locking pin engages theaperture when the seat bottom frame is in a seat configuration.
 4. Themethod of claim 1 further comprising the following steps: e) attaching alocking pin to the first attachment bracket; f) providing an aperture inthe second attachment bracket such that the locking pin engages theaperture when the seat bottom frame is raised to a storage accessconfiguration.
 5. A method of making an improved convertible sofa hingefrom a standard convertible sofa jack knife hinge, the jack knife hingeconnecting a seat back frame and a seat bottom frame to a seat baseframe including a side rail, the jack knife hinge having a seat backbracket fixably connected to the seat back frame, a seat bottom bracketfixably connected to the seat bottom frame, the seat back bracketpivotally connected to the seat bottom bracket, a first pivot armpivotally connected to the side rail and the seat back bracket, a secondpivot arm pivotally connected to the side rail and the seat bottombracket, the cross bar arm pivotally attached to the first pivot arm andthe second pivot arm, the method comprising the following steps: a)removing the seat back frame from the seat back bracket; b) fixablyattaching a first attachment bracket to the seat back frame; c)pivotally attaching the first attachment bracket to a second attachmentbracket; and d) fixably attaching the second attachment bracket to theseat back bracket.
 6. The method of claim 1 further comprising thefollowing steps: e) attaching a locking pin to the first attachmentbracket; f) providing an aperture in the second attachment bracket suchthat the locking pin engages the aperture when the seat back frame is ina seat configuration.
 7. The method of claim 1 further comprising thefollowing steps: e) attaching a locking pin to the first attachmentbracket; f) providing an aperture in the second attachment bracket suchthat the locking pin engages the aperture when the seat back frame islowered to an access configuration.
 8. A hinge assembly for aconvertible sofa, the hinge connecting a seat back frame and a seatbottom frame to a seat base frame including a side rail, the hinge for aconvertible sofa comprising: a seat back bracket fixably connected tothe seat back frame, a seat bottom bracket pivotally connected to theseat back bracket, a first pivot arm pivotally connected to the siderail and the seat back bracket, a second pivot arm pivotally connectedto the side rail and the seat bottom bracket, a cross bar arm pivotallyattached to the first pivot arm and the second pivot arm, a firstattachment bracket fixably attached to the seat bottom frame, a secondattachment bracket pivotally attached the first attachment bracket, andwherein the seat bottom bracket and the second attachment bracket arefixably attached to the seat base frame.
 9. The hinge assembly of claim8 further comprising: a third attachment bracket fixably attached to theseat back frame, a fourth attachment bracket pivotally attached thethird attachment bracket, and wherein the fourth attachment bracket isfixably attached to the seat back bracket.
 10. The hinge assembly ofclaim 8 further comprising: a locking pin attached to the firstattachment bracket; an aperture formed in the second attachment bracket;wherein the locking pin engages the aperture in the second attachmentbracket when the seat bottom frame is in a seat configuration,preventing movement of the seat bottom frame.
 11. The hinge assembly ofclaim 8 further comprising: a locking pin attached to the firstattachment bracket; an aperture formed in the second attachment bracket;wherein the locking pin engages the aperture in the second attachmentbracket when the seat bottom frame is raised to a storage accessconfiguration.
 12. The hinge assembly of claim 8 further comprising: aslot formed in the first attachment bracket; a pin projecting from thesecond attachment bracket through the slot formed in the firstattachment bracket; wherein the slot controls the movement of the firstattachment bracket with respect to the second attachment bracket. 13.The hinge assembly of claim 12, wherein the slot has at least oneportion formed as an arc.
 14. The hinge assembly of claim 12, whereinthe slot has at least one portion formed as a straight section.
 15. Ahinge assembly for a convertible sofa, the hinge connecting a seat backframe and a seat bottom frame to a seat base frame including a siderail, the hinge for a convertible sofa comprising: a seat back bracketfixably connected to the seat back frame, a seat bottom bracketpivotally connected to the seat back bracket, a first pivot armpivotally connected to the side rail and the seat back bracket, a secondpivot arm pivotally connected to the side rail and the seat bottombracket, a cross bar arm pivotally attached to the first pivot arm andthe second pivot arm, a first attachment bracket fixably attached to theseat back frame, a second attachment bracket pivotally attached thefirst attachment bracket, and wherein the second attachment bracket isfixably attached to the seat back bracket.
 16. The hinge assembly ofclaim 15 further comprising: a locking pin attached to the firstattachment bracket; an aperture formed in the second attachment bracket;wherein the locking pin engages the aperture in the second attachmentbracket when the seat back frame is in a seat configuration, preventingmovement of the seat back frame.
 17. The hinge assembly of claim 15further comprising: a locking pin attached to the first attachmentbracket; an aperture formed in the second attachment bracket; whereinthe locking pin engages the aperture in the second attachment bracketwhen the seat back frame is rotated downward from a seat configuration.18. The hinge assembly of claim 8 further comprising: a slot formed inthe first attachment bracket; a pin projecting from the secondattachment bracket through the slot formed in the first attachmentbracket; wherein the slot controls the movement of the first attachmentbracket with respect to the second attachment bracket.
 19. The hingeassembly of claim 12, wherein the slot has at least one portion formedas an arc.
 20. A convertible sofa comprising: a seat back frame; a seatbottom frame; a seat base frame including a side rail on opposite sidesof the seat base frame wherein the seat base frame encloses a storagearea; a pair of hinges connecting the seat back frame and the seatbottom frame to the seat base frame, wherein each hinge comprises a seatback bracket fixably connected to the seat back frame, a seat bottombracket pivotally connected to the seat back bracket, a first pivot armpivotally connected to the side rail and the seat back bracket, a secondpivot arm pivotally connected to the side rail and the seat bottombracket, a cross bar arm pivotally attached to the first pivot arm andthe second pivot arm, a first attachment bracket fixably attached to theseat bottom frame, a second attachment bracket pivotally attached thefirst attachment bracket; wherein the seat bottom bracket and the secondattachment bracket are fixably attached to the seat base.
 21. Theconvertible sofa of claim 20 further comprising: a third attachmentbracket fixably attached to the seat back frame, a fourth attachmentbracket pivotally attached the third attachment bracket, and wherein thefourth attachment bracket is fixably attached to the seat back bracket.22. The convertible sofa of claim 20 further comprising: a locking pinattached to the first attachment bracket; an aperture formed in thesecond attachment bracket; wherein the locking pin engages the aperturein the second attachment bracket when the seat bottom frame is in a seatconfiguration, preventing movement of the seat bottom frame.
 23. Theconvertible sofa of claim 20 further comprising: a locking pin attachedto the first attachment bracket; an aperture formed in the secondattachment bracket; wherein the locking pin engages the aperture in thesecond attachment bracket when the seat bottom frame is raised to astorage access configuration.
 24. The convertible sofa of claim 20further comprising: a slot formed in the first attachment bracket; a pinprojecting from the second attachment bracket through the slot formed inthe first attachment bracket; wherein the slot controls the movement ofthe first attachment bracket with respect to the second attachmentbracket.
 25. The convertible sofa of claim 24, wherein the slot has atleast one portion formed as an arc.
 26. A convertible sofa comprising: aseat back frame; a seat bottom frame; a seat base frame including a siderail on opposite sides of the seat base frame wherein the seat baseframe encloses a storage area; a pair of hinges connecting the seat backframe and the seat bottom frame to the seat base frame, wherein eachhinge comprises a seat back bracket fixably connected to the seat backframe, a seat bottom bracket pivotally connected to the seat backbracket, a first pivot arm pivotally connected to the side rail and theseat back bracket, a second pivot arm pivotally connected to the siderail and the seat bottom bracket, a cross bar arm pivotally attached tothe first pivot arm and the second pivot arm, a first attachment bracketfixably attached to the seat back frame, a second attachment bracketpivotally attached the first attachment bracket, and wherein the secondattachment bracket is fixably attached to the seat back bracket.